SPONGE: A Scalable Pivot-based On/Off Gating Engine for Reducing Static Power in NoC Routers

Abstract

Due to high aggregate idle time of Networks-on-Chip (NoCs) routers in practical applications, power-gating techniques have been proposed to combat the ever-increasing ratio of static power. Nevertheless, the sporadic packet arrivals compromise the effectiveness of power-gating by incurring significant latency and energy overhead. In this paper, we propose a Scalable Pivot-based On/Off Gating Engine (SPONGE) which efficiently manages power-gating decisions and routing mechanism by adaptively selecting a small set of powered-on columns of routers and keeping the others in power-gated state. To this end, a router architecture augmented with a novel routing algorithm is proposed in which a packet can traverse powered-off routers without waking them up, and can only turn in predetermined powered-on routers. Experimental results on SPLASH-2 benchmarks demonstrate that, compared to the conventional power-gating method, SPONGE on average not only improves static power consumption by 81.7%, it also improves average packet latency by 63%.